Gaseous electric discharge device



Feb. 14, 1933. M PlRAN: 1,897,497

GASEOUS ELECTRIC DISCHARGE DEVICE Filed Aug. 5, 1931 v v v I I INVENTOR ATTORNEY Patented Feb. 14, 1933 UNITED STATES IPATENTF-JOFFICE MARCELLO PIRANI, OF IBEBLIN-W'ILMERSDORF, GERMANY, ASSIGNOR '10 ELEGPRIC COMPANY, A CORPORATION OF NEW YORK GENERAL GASEOUS ELECTRIC DISCHARGE DEVIOE Application filed August 5, 1931, Serial No. 555,288, and in Germany September 12, 1830.

The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to means for feeding gas replenishments to such devices and is an improvement on my copend ing application Serial Number 381,036, filed July 25, 1929, being the invention of Marc'ello Pirani and Kurt Nitschke.

It is well known in the art that common gas 1 present in the gaseous filling of gaseous electric discharge devices has a tendency to clean up during the operation of the device with disasterous efiects to the operating characteristics thereof. It is as equally well known in the art that the means used for feeding gas replenishments to the gaseous filling of the electric discharge device must be accurate so that the gas replenishments fed thereto closely approximate the amount neededjo maintain the gas pressure substantially constant. The object of the present invention is to provide a simple, positive acting, accurate and sensitive gas feeding means for feeding gas replenishments to the gaseous atmosphere of a gaseous electric discharge device. A further object of the invention is to provide such a gas feeding means which is especially useful in connection with gaseous electric discharge devices having a high vacuum in the discharge container thereof. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from an inspection of the 5 accompanying drawing and from the following detailed description.

In accordance with this obj eat the invention comprises a narrow throat provided between the container of the gaseous electric discharge 40 device and a gas reservoir chamber fused to said container. A valve is provided to close the mouth of said throat, said valve consists of a stopper element to hermetically close the mouth of said throat, a bimetallic strip which bends when heated, and a means to heat said strip. The heating means and the stopper element are attached to opposite ends of said bimetallic strip. Said heating means is cut into and out of the current supply circuit of the electric discharge device automatically, or manually, as desired, to feed gas replenishments to the gaseous electric discharge device when needed.

In the drawing accompanying and forming part of this specification an embodiment of the invention is shown in which,

Fig. 1 is a side elevational view of a complete electric discharge device, made in accordance with the present invention.

Fig. 2 is an enlarged view of the valve partly in section, and

Fig. 3 is an enlarged top ,view of the valve showing the construction thereof in detail.

Like numbers denote like parts in all the fi ures.

Referringto the drawing the gaseous electric discharge device consists of a discharge container 1 having suitable electrodes sealed therein. A gas reservoir chamber 2 is fused to said container 1 by tube 3. A capillary tube 4: is fused into said tube 3, the mouth of said capillary tube 4: beingclosed by stopper element 85 attached to bimetallic strip 6 as shown in Fig. 2. Said strip 6 is arranged in side tube 7 of said tube 3 and is provided with heater element 9 at the end thereof opposite that to which stopper element 85 is attached. Element 85 consists of two parts, part 5, which hermetically closes the mouth of tube a and which is of elastic material such as gum, parafined leather, cork, or like material impervious to the gas used, and a metal container 8 which holds part 5 on bimetallic strip 6.

Said heater 9, if desired, is cut into and out of the current circuit of the tube 1 by connecting leads 11 thereof to a means, such as a magnetic switch, controlled by current flowing in said tube 1 similar to that disclosed in my co-pending application referred to hereinbefore, so that the movements of bimetallic strip 6 and therewith the stopper element 85 are controlled by variations in current flowing in said tube circuit caused by changes in gas pressure in said tube 1. When heater 9 is cut into the circuit, due to a loss of gas pressure, bimetallic strip 6 is caused to bend slightly to move part 5 from the mouth of capillary tube 4 and gas seeps over into container 1 from reserve chamber 2 to 109 restore normal conditions of gas ressure to replenishment to said container from said the gaseous electric discharge evice. As reservoir. soon as normal conditions of gas pressure In witness whereof, I have hereunto set have been restored in tube '1 heater 9 is again my hand this 22nd day of July, 1931. I cut out of the current circuit of tube 1 so I ,MARCELLO PIRANI. 70

that strip 6 resumes its normal position in which position element 5 covers and her metically closes the mouth of tube 4. I have found that a very simple method 0 making the capillary tube 4 to provide a gas 7 passage of predetermined diameter is by thrusting a metal wire of the desired diame ter into a glass tube, said wire having a greater coefiicient of expansion than that of the 3 glass, heating said wire and said glass tube to the softening temperature of the glass so that the inner walls of the glass tube come into contact with the walls of the metal wire, and allowing said wire and said glass to cool slow- I! 1y. As the metal wire has a greater coefiicient of expansion than the glass tube said wire frees itself from the walls of said glass tube during the cooling process and may be removed therefrom at a suitable time leav- 5 ing a gas passage of predetermined diameter.

While I have shown a particular embodiment of my invention it will be understood of course that such illustration is primarily for purposes of disclosure and that numerous substitutions, modifications and changes in the form and details of the device and in its use and operation may be made by those skilled in the art without departure from the broad spirit and scope of the invention, for

' example, a plate of a material pervious to the gas may be used in place of. capillary gas tube 4.

What I claim as new and desire to secure by Letters Patent of the United States, is: a 1. A valve for feeding gas replenishments to the gaseous atmosphere of a gaseous electric discharge device comprising an element pervious to said gas, an element impervious to said gas and adapted to close said pervious element, a metal element carrying said gas impervious element and adapted to move when heated, and means to heat said metal element.

2. Avalve for feeding gas replenishments to the gaseous atmosphere of a gaseous electric discharge device comprising a gas passage, means to hermetically close said gas passage, a bimetallic strip carrying said 5 means and adapted to bend when heated, and

means to heat said bimetallic strip.

3. In combination an electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, a gas 00 reservoir therefor and means comprising a 5 gas passage, an hermetic stopper for said passage, a bimetallic strip carrying said stopper and adapted to bend when heated, and means controlled bycurrent flowing in said device to heat said strip to control the flow of gas 

